Packaging machine former

ABSTRACT

A packaging machine former apparatus  10  through which a film  11  passes to be formed into a tube  12.  The apparatus  10  includes a shoulder  15  over which the film  11  passes, the shoulder  15  including an approach member  16  that leads to a crown  17.  The member  16  includes a passage  20  terminating in an aperture  21  to which a gas under pressure is delivered so as to create an “air cushion” over which the film passes, thereby aids in movement of the film  11  over the surface  18  of the approach member  16.

TECHNICAL FIELD

[0001] The present invention relates to packaging machines and moreparticularly to former shoulders which receive film from a roll totransform the film into a tubular configuration for delivery to amachine which forms discrete packages containing product.

BACKGROUND OF THE INVENTION

[0002] Packaging machines such as those described in U.S. Pat. Nos.4663917, 4423858, 4391081, 3070931 and 3850780 employ formers whichtransform plastic film (strip) into a tubular configuration. The film ispulled through the former by means of a film drive unit. Typically thefilm drive unit will engage the tubular material by means of rollers andbelts such as that discusses in U.S. Pat. No. 4910943. It is also knownto move the tubular bag material through the packaging machines by meansof engagement with the jaws of the packaging machine.

[0003] A former includes a forming shoulder over which the film passes.Problems are often encountered with this relative movement which canresult in a variation in the force required to move the film over andthrough the former Preferably the force required is constant and is notexcessive. These problems are exacerbated in the case of heavy gaugefilm as well as film that may be relatively stiff. Humidity and staticcharge also influence the force required to be applied to the film.

[0004] A further problem to the above is that frequently formers willsmudge any printed material applied to the film.

OBJECT OF THE INVENTION

[0005] It is the object of the present invention to overcome orsubstantially ameliorate at least one of the above disadvantages.

SUMMARY OF THE INVENTION

[0006] There is disclosed herein a shoulder for a packaging machineformer, said shoulder including:

[0007] a crown over which film passes to be arranged in a tubularconfiguration; and

[0008] an approached member extending to said crown and having a surfacepast which the film moves in approaching said crown, said member havinga passage extending to said surface through which a gas under pressureis delivered to deliver said gas to an area between said surface andsaid film.

[0009] Preferably the said passage terminates with an aperture locatedgenerally centrally in said surface

[0010] A one preferred form there is a plurality of said passagesextending to said surface through which said gas is delivered so thatsaid gas is delivered to an area between said surface and said film.

[0011] Preferably said shoulder further includes a valve to deliver saidgas to said passage, said valve being adapted to govern the pressure ofsaid gas delivered to said surface.

BRIEF DESCRIPTION OF THE DRAWINGS

[0012] A preferred form of the present invention will now be describedby way of example with reference to the accompanying drawings wherein:

[0013]FIG. 1 is a schematic perspective view of a former apparatus of apackaging machine;

[0014]FIG. 2 is a schematic perspective view of film passing through theapparatus of FIG. 1;

[0015]FIG. 3 is a section schematic side elevation of the apparatus andfilm of FIGS. 1 and 2;

[0016]FIG. 4 is a further schematic perspective view of the film andapparatus of FIGS. 1 and 2;

[0017]FIG. 5 is a further schematic perspective view of the apparatusand film of FIGS. 1 and 2; and

[0018]FIG. 6 schematically depicts a modification of the apparatus ofFIGS. 1 to 5.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] In the accompanying drawings there is schematically depicted aformer apparatus 10 through which a web of film 11 passes to be formedinto a tube 12. The tube 12 passes through a packaging machine andreceives a product which is to be packaged by the packaging machine. Theproduct to be packaged is delivered to the upper aperture 13 of the tube12, with the tube 12 being subsequently scaled along the back seam andat spaced locations to form discrete packages.

[0020] The apparatus 10 includes a base 14 which supports a shoulder 15over which the film 11 passes. The shoulder 15 includes an approachmember 16 which leads to a crown 17 over which the film 11 passes to beconfigured to form the tube 12. The member 16 has an upper surface 18past which the film 1 moves in its passage to the crown 17.

[0021] The film 11 is removed from a roll and first engages a roller 19before delivery to the surface 18.

[0022] The member 16 is provided with a passage 20 terminating at itsend with a generally centrally located aperture 21. The aperture 21 isin the surface 18. Extending from the passage 20 is a duct 22communicating with an airflow control valve 23. The valve 23 receives agas (typically air) under pressure. The valve 23 governs delivery of airto the passage 20 and therefore the aperture 21. Air leaving theaperture 21 enters an area 24 between the surface 18 old film 11. Thisaids movement of the film 11 over the surface 18 by creating an “aircushion” over which the film 11 passes. This reduces frictionalengagement between he surface 18 and the film 11. As best seen in FIGS.4 and 5, the air escapes laterally relative to the longitudinaldirection 25 of movement of the film 11.

[0023] If so required, there may be a plurality of the passages 20 andassociated apertures 21, with the apertures distributed over the surface18.

[0024] Extending from the valve 23 is a duct 26 which attaches theapparatus 10 to a supply of gas under pressure.

[0025] In respect of the delivery of gas to the valve 23, it should beappreciated that the flow of gas could be pulsed if so required. Stillfurther, the gas could be heated or chilled to increase or decrease thestiffness of the film 11. Still further, heating of the film 11 may aidin the drying of ink.

[0026] In a further embodiment (as shown in FIG. 6), one or moreapertures 21 are formed in the surface 18, each with an associatedpassage 20 extending from the duct 22

The claims defining the invention are as follows:
 1. A shoulder for apackaging machine former, said shoulder including: a crown over whichfilm passes to be arranged in a tubular configuration; and an approachedmember extending to said crown and having a surface past which the filmmoves in approaching said crown, said member having a passage extendingto said surface through which a gas under pressure is delivered todeliver said gas to an area between said surface and said film.
 2. Theshoulder of claim 1, wherein said passage terminates with an aperturelocated generally centrally in said surface.
 3. The shoulder of claim 1,wherein there is a plurality of said passages extending to said surfacethrough which said gas is delivered so that said gas is delivered to anarea between said surface and said film.
 4. The shoulder of claim 1further including a valve to deliver said gas to said passage, saidvalve being adapted to govern the pressure of said gas delivered to saidsurface.
 5. A packaging machine former including a shoulder according toclaim
 1. 6. A packaging machine former substantially as hereinbeforedescribed with reference to the accompanying drawings.